1. Field of Use
This invention relates generally to fasteners for attaching apertured panels. In particular, it relates to fasteners with heads that are rotatably engageable into one of the apertured panels, the heads formed so as to provide maximum support to the panel and so as to prevent inadvertent removal of the head from that panel.
2. Description of Prior Art
Several fasteners with heads substantially larger than the apertures through which the heads are inserted are currently in use. Most have lead-in tongues which are inserted through a hole in a panel member, and a twisting motion imparted to the fastener's shank properly positions the head in its panel. The opposite or shank end of the fastener is then ready for insertion, as by pushing, through the aperture of a support member. Typically, these fasteners have a head in the form of a flange of which the edge is recessed radially inwards on one side, and the head is inserted at one of the two corners at the recess, as shown in U.S. Pat. No. 3,309,955, issued to Turnbull et al on Mar. 21, 1967, hereinafter referred to as Turnbull. FIG. 5 in that patent shows the head being inserted at one of the two corners of the recess, which is generally approximately V-shaped and can be as small as a straight or curved, substantially radial cut through the flange, as shown in U.S. Pat. No. 3,225,641, issue to Harris et al on Dec. 28, 1965, or as large as 140.degree., as illustrated by the 90.degree. V-notch shown in FIG. 2 of Turnbull.
These current heads have some significant disadvantages. A large V-notch in such a head provides the fastener with less support when the head is in place in the panel member. The head, and thus the fastener, may tip or cant or have one of the two recess corners drop back into the panel member's aperture, and the head may then fall out of that aperture rendering the fastener useless. Even if the V-notch is reduced in size to 0 degrees by the use of a mere slit in the head, the head may still become disengaged from the panel in the manner described above if the panel is made of a resilient material.